Zinc (Zn) is a metallic element that is very important for good health. It is involved in many processes in the body and controls the functioning of many enzymes. The average human adult contains 2-4g of zinc, of which 78 per cent is held in the bones, muscles and the skin. These tissues store the mineral, and if a deficiency of the mineral arises then the zinc is released. Hence, we require a daily intake of zinc in our diet.
The RDA for zinc is 15mg for adults, but most people do not get this level in their diet. Groups particularly at risk of insufficient zinc are growing children, the elderly, pregnant women, vegetarians and people suffering from chronic illnesses or allergies. During pregnancy and breast-feeding, the levels of zinc required rise by 50 to 75 per cent to 23-27mg daily. Zinc is found in liver, red meat, egg yolk, whole-grain flour, seafood (especially oysters), dairy produce, vegetables, and cereals and their products. The percentage of zinc absorbed in the body is variable, and in a mixed diet of meat and vegetables roughly 15-40 per cent of the zinc intake is absorbed.
Zinc in vegetables is not absorbed as well, so vegetarians are at a particular risk of deficiency, and supplementation may be sensible. The best form of zinc, which is absorbed well, is organic zinc, normally as gluconate or aspartate salts. Care should be taken with zinc supplements as zinc competes with copper, and higher levels of zinc intake can reduce the absorption of copper. Any zinc supplement of more that 30mg daily taken to augment the dietary intake should be combined with a small supplement of copper to prevent any problems arising. Zinc is taken in via the intestines and is removed from the body with secretions from the gall bladder and pancreas and with the excreted material. Loss of zinc increases because of diabetes, dialysis treatment, diuretic medicine, some anti-arthritis medicines and excessive sweat production. Tissue damage caused by kidney diseases, flaking skin diseases or burns also cause more zinc to be lost from the body.
